The present invention is directed to a cerclage tool, and in particular to an instrument used to position a cerclage wire around a bone for fixation of a fracture such that when the instrument is inserted into the patient, the disruption of surrounding muscle tissue is minimized.
The use of cerclage wires for internal fixation of bone fractures is a well-known technique. Cerclage wiring techniques are frequently used following reduction for provisional fixation of long bone fractures to stabilize the bone for placement of screws, nails or rods, after which the wires are removed. They may also be used for definitive bone fixation, either alone or in combination with other fixation devices.
Cerclage wires are passed around the bone using a wire passer or cerclage tool, so as to lie as perpendicular to the long axis of the bone as possible. Typically, a wire passer or cerclage tool is an instrument having a shaft with a curved end and an eyelet or notch in the curved end for guiding the wire around the bone. These wire passers are available in different curvature diameters and can therefore be used with larger or smaller diameter bones.
Surgical procedures on and in the vicinity of a bone with closely neighboring nerves, arteries, muscle, ligaments, complicated anatomical structures, and other delicate areas represent a difficult and time consuming task for a surgeon.
The difficulty with these procedures is that they need to be performed accurately, minimizing stress, trauma, risk, and injury to a patient, and with as little difficulty for a surgeon performing such procedures, in as rapid a time frame as possible.
The orthopedic procedure is as follows: the curved end of the instrument is positioned around the bone and a wire is inserted into the eyelet so that it can be pulled around the bone as the instrument is withdrawn. After the wire has encircled the bone, the ends are twisted using wire tighteners.
Different surgical tools are known in the art. However, none of the tools adequately satisfies these aforementioned needs. Different instruments have been devised to pass the wire around a bone. Most of the surgical tools known in the art have a handle structure with either a “C” or “S” shaped portion. Some of these instruments, such as that disclosed in U.S. Pat. No. 5,772,663 include a hollow or grooved part for guiding the orthopedic wire therethrough after the instrument is accurately positioned around the bone. As described in U.S. Pat. Nos. 4,606,335 and 5,501,668, other instruments include an eyelet opening at the free end of the curve through which the wire is threaded during the cerclage procedure.
Most of the cerclage devices in the prior art are designed with a curvature to partially encircle the bone shaft and are formed from rigid materials. At certain points in their travel around the bone, these cerclage devices can create a lever action which causes pulling of the soft tissue away from the bone and/or significant spreading of the incision.
For example, U.S. Pat. Nos. 4,606,335, 5,772,663 and 5,501,688 require a significant spreading of an incision in order to allow the tip of the device to completely travel around the bone for insertion of the wire into the eyelet, thus causing trauma to the muscle.
The cerclage wire passer disclosed in the U.S. Pat. Nos. 5,810,832 and 5,851,209 provides a flexible, retractable tip that curves around and adapts to the bone circumference, apparently solving the problem of significant spreading of the incision and muscle trauma. However, these devices have insufficient strength to go through the bone surrounding muscles.
U.S. Pat. No. 4,312,337 shows a scissor-like apparatus that claims to minimize the amount of soft tissue that has to be separated from bone to insert a cerclage wire. However, this device does not position the wire around the bone, but instead, through the bone cortex. It does not perform the same function as that of the present invention and still results in too much tissue and muscle trauma
The effectiveness of the cerclage wire has proven itself, but the cerclage procedure itself has proved difficult in many cases. The heretofore instruments fail to provide an adequate technique for positioning a cerclage wire around a bone and may lengthen the overall procedure significantly.
To overcome the foregoing deficiencies of these devices, a new cerclage wire passer is needed that takes into consideration the fact that the wire must be passed around the bone in a simple and reliable manner, without spreading the incision or requiring a large incision to provide the range of movement necessary to guide a rigid trip around the bone without excessive intrusion, exposure or stripping of the bone-surrounding musculature. In addition, a new cerclage wire passer is needed that allows a surgeon to more quickly perform such procedures.